Where's the documentation for Ctrl-C while in [Command Line] buffer?

Question

Long ago I discovered that q: opens a [Command Line] buffer where I can enter and edit an ex command line using all the power of Vim.

Next, some time ago, I discovered that I can access that mode even while in the middle of editing a command line by pressing Ctrl+f.

For all the above I've found the doc.

But today, I've discovered that hitting Ctrl + C while in that window, the line being edited is copied on the ex prompt which becomes active. It's a bit like it's the inverse of Ctrl+f.

However, I couldn't find the documentation for it. Can you enlighten me?

Answer 1

For example, type :h q:. It takes you to the file cmdline.txt near the top of the section #7 "Command-line window".

The whole section is, obviously, 100% relevant to the topic. The <C-C> keybinding is mentioned a pair of page-downs under.

Speaking in general, there are 3 main ways:

1. Press F1. Then scroll down to "REFERENCE MANUAL". Find relevant help file. Browse through the contents, use /, n, N etc. Probably, this is too boring, but I had to mention this.

2. If you clearly remember something that must be tagged, such as :command then type :h :command (also, make some use of "tab"-completion), look around, follow the links with <C-]> and <C-T> etc.

And even when you're not sure, just naive typing :h something could help you a lot.

3. If you still have no idea then go with :h :helpgrep.

Answer 2

After :help q: and scrolling down a bit:

CLOSE                           *E199*

There are several ways to leave the command-line window:

<CR>        Execute the command-line under the cursor.  Works both in
        Insert and in Normal mode.
CTRL-C      Continue in Command-line mode.  The command-line under the
        cursor is used as the command-line.  Works both in Insert and
        in Normal mode.  There is no redraw, thus the window will
        remain visible.
:quit       Discard the command line and go back to Normal mode.
        ":close", CTRL-W c, ":exit", ":xit" and CTRL-\ CTRL-N also
        work.
:qall       Quit Vim, unless there are changes in some buffer.
:qall!      Quit Vim, discarding changes to any buffer.

Once the command-line window is closed the old window sizes are restored.  The
executed command applies to the window and buffer where the command-line was
started from.  This works as if the command-line window was not there, except
that there will be an extra screen redraw.
The buffer used for the command-line window is deleted.  Any changes to lines
other than the one that is executed with <CR> are lost.

If you would like to execute the command under the cursor and then have the
command-line window open again, you may find this mapping useful: >

    :autocmd CmdwinEnter * map <buffer> <F5> <CR>q: